Polaris Dawn

The Polaris program was announced by Jared Isaacman in February 2022, five months after the first all-private astronaut mission, Inspiration4, which was also financially backed by Isaacman.^[2][3] Development of several technologies necessary for the mission is also part of the program, including extravehicular activity (EVA) spacesuits for private astronauts, intersatellite laser communication links between the Dragon spacecraft and the Starlink constellation, and some accommodation for the lack of an airlock in the legacy Dragon capsule design.^[4]

Originally slated to fly as early as late 2022, the program suffered delays over the design of the EVA spacesuits and technical problems with SpaceX testing inter-satellite laser communication links. By October 2022, the launch had already slipped to March 2023,^[5][6] and by February 2023, had slipped to no earlier than mid-2023.^[7][8] By mid-2023, the planned date had slipped to sometime in 2024,^[9] with Isaacman confirming in December a launch date of April 2024.^[4] On 7 June, in an interview, Isaacman announced that the launch was scheduled to launch no earlier than 12 July 2024.^[10][11] Three weeks later, the Polaris program announced on its X account that the earliest target launch date was 31 July 2024.^[12][13]

The mission was delayed again following the failure of a Falcon 9 rocket's upper stage on 12 July 2024. After SpaceX addressed the cause of the mishap, SpaceX's Dragon mission management director Sarah Walker announced in a 26 July news conference that Polaris Dawn would launch "in late summer" after the Crew-9 mission for NASA, which was scheduled to launch no earlier than 18 August before its delay.^[14] SpaceX then said that it was targeting a 26 August launch date on 7 August.^[15] SpaceX pushed the launch date back a day to 27 August in order to allow "additional time for teams to complete preflight" checkouts.^[16][17]

Crew Dragon Resilience arrived at the horizontal integration facility at LC-39A on 21 August where it was integrated with Falcon 9 booster B1083 and a second stage.^[18] The transporter erector rolled out of the horizontal integration facility in the early morning hours of 24 August to transport the rocket up to the pad and erect it next to the tower.^[19] The crews completed a dry dress rehearsal and static fire tests on 25 August.^[20][21]

To minimize the risk of micrometeorite impacts, SpaceX mission controllers have a flexible launch window for the Polaris Dawn mission, allowing them to select a time with minimal debris in the targeted orbit. The Dragon capsule will initially be placed in a highly elliptical orbit, taking the crew as far as 1,200 kilometers (750 mi) from Earth and passing through the South Atlantic Anomaly at a low altitude of 190 kilometers (120 mi). This will expose them to the equivalent radiation of three months on the International Space Station in just a few passes, enabling valuable research into the health effects of space radiation and spaceflight on the human body.^[22][23]

Within an hour after launch, the crew will begin a pre-breathing protocol to reduce nitrogen in their bodies and minimize the risk of decompression sickness during the planned spacewalk on day three. Over three days, the cabin pressure will gradually decrease from 14.5 to 8.65 pounds per square inch (100.0 to 59.6 kPa) while oxygen levels increase.^[1]

During this first hour in space, the crew will conduct thorough checks of the Dragon capsule for any launch-related damage. If no issues are found, the Draco thrusters will fire, propelling the crew up to 1,400 kilometers (870 mi) away from Earth, the highest orbit of the planet ever flown by a crewed spacecraft, breaking the record set by Gemini 11,^[24] and the farthest anyone has been from Earth since NASA's Apollo program.^[25][4] They will remain at this orbit for approximately ten hours.^[1]

On flight day two, the Dragon's apogee will be lowered to its "cruising orbit" of 750 kilometers (470 miles) while the crew prepares their EVA suits and conducts experiments.^[23][1]

Flight day three is dedicated to the first-ever extravehicular activity (EVA) on a commercial spaceflight mission. After extensive preparations, all four crew members will don their EVA suits, which are pressurized with 100% oxygen at 5.1 pounds per square inch (35 kPa). The Crew Dragon will then be fully depressurized, and Jared Isaacman and Sarah Gillis will have the opportunity to go out for 15 to 20 minutes each to conduct various tests of the EVA suit.^[1]

SpaceX designed the EVA suits for this mission based on the intravehicular activity (IVA) suits typically worn during launch and landing. The EVA suits are designed to keep astronauts safe in the vacuum of space while also being comfortable and flexible enough for launch and landing, eliminating the need for separate IVA suits. Flame-resistant, stretching fabric and soft joints provide mobility, while boots are made from the same thermal material used on Falcon 9's interstage and Dragon's trunk.^[26][27] Compared to the IVA suits, thermal management has been improved and the helmet has received thermal insulation and an anti-fog treatment. During the spacewalk, a heads-up display will provide information on suit metrics.^[28] An umbilical will provide life support for these suits, similar to early Gemini suits, as opposed to the self-contained EMUs used on the ISS.^[29][30]

Since Crew Dragon capsules lack an airlock, several modifications have been made to the interior of Resilience. Extra nitrogen and oxygen tanks have been installed, a hatch with a ladder called the "skywalker" has replaced the docking port, and the forward hatch has been motorized. All four astronauts will wear EVA suits, though only two will exit the spacecraft.^[23] This mission will break the record for the most people in the vacuum of space at once, set at three during Apollo 15 when the Command Module was depressurized for Al Worden's EVA.^[28][29] Due to the unique depressurization protocol, the crew plans to conduct research on decompression sickness and spaceflight associated neuro-ocular syndrome (SANS).^[31]

To validate their procedures, Resilience underwent multiple cycles of venting and repressurization in a large vacuum chamber. The crew also spent two days in a chamber validating their pre-breathing protocol and wearing their EVA suits in a vacuum.^[1]

The mission will also be the first crewed operational test of Dragon laser interlink communication via Starlink. If successful, it would potentially decrease communication latency and increase data bandwidth for human spaceflight.^[32]

Isaacman will lead the mission as Commander, with retired Air Force fighter pilot Scott Poteet serving as spacecraft pilot. Isaacman will primarily operate the spacecraft, with Poteet acting as his backup. This role allocation is critical given the mission's inclusion of a spacewalk to be conducted by Isaacman.

Completing the crew are SpaceX employees Sarah Gillis and Anna Mennon as Mission Specialists. Gillis, the company's senior space operations engineer who also leads training of private spaceflight missions, will join Isaacman on the spacewalk. Menon, a lead space operations engineer and mission director for the company, will act as onboard medical officer for the mission, tapping into her six years of experience as a biomedical flight controller at NASA, where she oversaw International Space Station operations.

Polaris Dawn is planned to launch from Kennedy Space Center Launch Complex 39A on a Falcon 9 Block 5 rocket.^[33][34] The first launch attempt on 27 August 2024 was scrubbed due to a ground-side helium leak.^[35] The second launch attempt on 28 August was scrubbed due to poor predicted weather during the recovery period five days after launch. Because the mission will not rendezvous with the International Space Station and has limited life support consumables, the capsule must be able to splashdown as scheduled; this necessitates favorable weather conditions.^[36] As of 27 August 2024, a new launch date has not yet been set, with SpaceX saying it was monitoring the weather for favorable launch and return conditions.^[37] On 28 August, the Federal Aviation Administration grounded the Falcon 9 after a first stage crashed on landing, delaying the launch indefinitely.^[38][39] Two days later, the Falcon 9 was cleared to resume flights while the FAA continues investigating.^[40]

Note: times are local to the launch site (Eastern Daylight Time).

• Inspiration4
• Timeline of private spaceflight

• Official website  
• Polaris Program photos on Flickr